It was a time of economic struggle, racial resentment and increasing xenophobia. Installed in the White House was a president who had never before held elected office. A moderately successful businessman, he promised American jobs for Americans—and made good on that promise by slashing immigration by nearly 90 percent.

He wore his hair parted down the middle, rather than elaborately piled on top, and his name was Herbert Hoover, not Donald Trump. But in the late 1920s and early 1930s, under the president’s watch, a wave of illegal and unconstitutional raids and deportations would alter the lives of as many as 1.8 million men, women and children—a threat that would seem to loom just as large in 2017 as it did back in 1929.

What became colloquially known as the “Mexican repatriation” efforts of 1929 to 1936 are a shameful and profoundly illustrative chapter in American history, yet they remain largely unknown—despite their broad and devastating impact. So much so that today, a different president is edging towards similar solutions, with none of the hesitation or concern that basic consciousness would seem to require.

Indeed, in the last several weeks, President Trump ordered the Department of Homeland Security to greatly increase not only the scope of potential deportees, but the speed at which they are being sent out of the country—a bid at “stabilization” borne of many of the same nationalist anxieties that plagued his predecessor nearly a century ago.

In his address to a joint session of Congress last week, the president painted a dark portrait of America’s immigrant population: “As we speak tonight,” he intoned, “we are removing gang members, drug dealers and criminals that threaten our communities and prey on our very innocent citizens.” It was the same foreboding message that Trump has espoused since he announced his candidacy, and yet there remains very little evidence to support it.

Several weeks ago, Trump’s White House circulated a draft executive order aimed at “protecting U.S. jobs,” one that would shut America’s doors to immigrants most likely to require public assistance (including reduced school lunches) as well as tightly control who is able to enter the American workforce. It was very nearly Hoover’s rallying cry—American jobs for Americans—heard once again.

Protecting our workers also means reforming our system of legal immigration. The current, outdated system depresses wages for our poorest workers and puts great pressure on taxpayers. Nations around the world, like Canada, Australia and many others, have a merit-based immigration system. It’s a basic principle that those seeking to enter a country ought to be able to support themselves financially. Yet in America we do not enforce this rule, straining the very public resources that our poorest citizens rely upon.

Back in Hoover’s era, as America hung on the precipice of economic calamity—the Great Depression—the president was under enormous pressure to offer a solution for increasing unemployment, and to devise an emergency plan for the strained social safety net. Though he understood the pressing need to aid a crashing economy, Hoover resisted federal intervention, instead preferring a patchwork of piecemeal solutions, including the targeting of outsiders.

According to former California State Senator Joseph Dunn, who in 2004 began an investigation into the Hoover-era deportations, “the Republicans decided the way they were going to create jobs was by getting rid of anyone with a Mexican-sounding name.”

“Getting rid of” America’s Mexican population was a random, brutal effort. “For participating cities and counties, they would go through public employee rolls and look for Mexican-sounding names and then go and arrest and deport those people,” said Dunn. “And then there was a job opening!”

“We weren’t rounding up people who were Canadian,” he added. “It was an absolutely racially-motivated program to create jobs by getting rid of people.”

Why, specifically, men and women of Mexican heritage? Professor Francisco Balderrama, whose book, ADecade of Betrayal: Mexican Repatriation in the 1930s is the most definitive chronicle of the period (and, not coincidentally, one of the only ones), explained: “Mexican immigration was very recent. It goes back to that saying: Last hired, first fired. The attitude of many industrialists and agriculturalists was reflected in larger cities: A Mexican is a Mexican.” And that included even those citizens of Mexicans descent who were born in the U.S. “That is sort of key in understanding the psychic of the nation,” said Balderrama.

The so-called repatriation effort was, in large part, a misnomer, given the fact that as many as sixty percent of those sent to “home” Mexico were U.S. citizens: American-born children of Mexican-descent who had never before traveled south of the border. (Dunn noted, “I don’t know how you can repatriate someone to a country they’ve not been born or raised in.”)

“Individuals who left at 5, 6 and 7 years old found themselves in Mexico dealing with process of socialization, of learning the language, but they maintained an American identity,” said Balderrama. “And still had the dream to come back to ‘my country.’”

The raids, as detailed in Balderrama’s chronicle, were vicious. With national concerns over the supposed burden that outsiders were putting on social welfare agencies, authorities targeted those Mexicans utilizing public resources. “In Los Angeles,” explained Balderrama, “they had orderlies who gathered people [in the hospitals] and put them in stretchers on trucks and left them at the border.”

The efforts were equally chaotic. “The first raid in Los Angeles was in 1931—they surrounded La Placita Park near downtown L.A.,” Dunn recalled. “It was a heavily Latino area. They, literally, on a Sunday afternoon, rounded everyone up in park that day, took them to train station and put them on a train that they had leased. These people were taken to Central Mexico to minimize their chances of crossing the border and coming back to the U.S.”

Dunn continued, “It was not like there was a master committee mapping out blocks. It was more fly-by-the-seat-of-the-pants. As in, Here’s a park where Mexicans go, okay let’s go there.”

Mexicans in the United States—and Americans of Mexican descent—had little understanding of what was happening, and what their rights were. Elena Herrada, one of the founders of the oral history project, “Los Repatriados: Exiles from the Promised Land,” is the grandchild of Mexican-Americans who were targeted in the raids. Her grandparents, she recalled, lived in a “mostly Mexican neighborhood” in Detroit, known as Court Town.

“It was the welfare officials who were doing it. A worker came to the door,” Herrada said. “My father remembered his father being asked by the worker, Where are you from?”

“My dad was really puzzled,” she said. “Because his father didn’t want to say ‘Mexico’. My father was confused because he had always been a proud Mexican.”

The family, Herrada recounted, was “de-patriated” to Mexico.

“My grandfather didn’t have work at the time, and they were forcing them to leave. There was no gun put to his to head, but [they said he] wouldn’t be eligible to receive assistance—and he would starve.”

“Many people didn’t believe they had a choice,” Herrada explained, “so they didn’t resist. My family didn’t believe they had a choice.”

Herrada’s father and uncle would spend two years in Mexico before his parents were able to bring him back to the United States—after her grandfather, a veteran of the U.S. Army, returned to the country and once again found work.

If American deportees made it back to America, according to Dunn, it was often because a friend or family member back in the States managed to obtain a copy of their birth certificate, proof of citizenship. And if they weren’t U.S. citizens, by the onset of World War II and the departure of much of the able-bodied workforce to the front, Mexican labor was back in demand: bodies were needed for low-paying agricultural work, and the xenophobia subsided under the auspices of the Bracero Program (a bilateral agreement between the U.S. and Mexico, the program brought Mexican workers to the states for short-term labor).

But some never made it back to America. “We are who we are because of what people did in that moment,” said Herrada.

Each state handled the raids differently—sometimes federal agents were involved, sometimes it was social workers and local law enforcement who targeted people for removal. Hoover’s precise role in directing the deportation efforts is unclear, but, according to Professor Kevin Johnson, Dean of the UC Davis School of Law, and a specialist in public interest law and Chicano studies, “There was a lot of correspondence between the different levels of government, and there was logistical support.” This support included reimbursing states for the chartering of busses and trains to transport people to Mexico.

Deportations took place across the country: Los Angeles had the largest concentration of Mexicans and Mexican-born Americans, but communities in Detroit were also targeted in large number. “America’s most industrial city was in many ways the promise of the age in terms of economic prosperity,” according to Balderrama, and because of this, its Mexicans and citizens of Mexicans-descent were not exempt from deportation. “The archival evidence points to a full map, across the nation,” said Balderrama. There were deportations in states as far flung as Alaska, Alabama and Mississippi.

And yet, confirming the precise number of people who were deported during this era is difficult, said Balderrama. “Both governments”—Mexico and the United States—“weren’t very interested in keeping records about what happened. It was a problem and they wanted to get rid of it. That’s why the numbers are very difficult.”

Dunn, however, spent nearly three years doing archival research, enlisting his state senate staff to comb through federal, state and local records in a bid to reconcile California’s tortured legacy. He feels confident in his citation of 1.8 million people deported. “That number came out of several documents we got from the federal government,” he told me.

Beyond the travesty inflicted upon hundreds of thousands of U.S. citizens, the Mexican deportations of the 1920s and 1930s are also shocking—and at this moment, particularly enlightening—for the illegalities visited upon non-citizens. Trump is unlikely to willfully deport American citizens, but he appears perilously close to replicating many of the mistakes Hoover did as it concerned the undocumented. And given the number of mixed-status families in the U.S.—as of 2015, 16.6 million Americans lived in residences with at least one undocumented immigrant—these deportations will affect citizens and non-citizens alike.

Johnson said that in hindsight, it is clear Hoover’s deportations were a violation of “several constitutional rights,” including the Fourteenth Amendment’s due process clause and the Fourth Amendment, which prohibits unreasonable search and seizure.

“Now it’s very clear that some of those provisions apply to immigrants in the U.S. The Supreme Court has made very clear that as long as you’re in the U.S., you have a right to due process and hearing. That doesn’t mean you can’t be removed,” said Johnson. “But you have the ability to retain counsel.”

Johnson said that many immigrants—especially those who have been here for any extended amount of time, may have “deep community ties—to citizens, churches, employers.” The longer someone is in the U.S., he explained, “the more of those ties you have, and the deeper your rights are.”

He pointed out that this legal reality, “is an issue right now because the White House is making efforts to expedite and expand deportations. But it means no hearing, no judicial review; it could be ready as a summary deportation.”

Further, the expedited deportations can now occur beyond one hundred miles of the U.S.-Mexico border, and can target people who have been here for as many as two years. “Imagine what can happen in two years,” said Johnson. “All kinds of relief you might be eligible for, but you might not even have a hearing. The reason you have hearings is to try and avoid mistakes: If you don’t … you are probably going to have some mistakes tolerated and accepted.”

Perhaps more than anything, the humanitarian cost of the Hoover-era deportations are the specter that looms largest over Trump’s immigration policy of today. Given the burden mass deportations would have placed on the federal bureaucracy, Hoover’s administration outsourced the raids, targeting and deportation to local and state officials—persons not particularly well versed in constitutional law, nor the sensitivities surrounding deportation.

Trump appears ready to do the same: while the administration has directed the hiring of 10,000 new Immigration and Customs Enforcement (ICE) officials to oversee the dramatic increase in deportations, the administration has also revived the controversial 287(g) program, which recruits local law enforcement and sheriff’s deputies to assist in deportations.

“It’s frightening and terrifying,” said Johnson. “We have a recent history—one not limited to the 1930s—of law enforcement engaging in excess in the name of law enforcement.”

“I may be suspicious of ICE officials and how they apply the law,” he added, “but I do think they are trained to enforce the laws. And it’s the job of state and local police to enforce criminal laws—they don’t have the training, expertise or sensitivity to enforce accurate immigration decisions.”

And yet it’s unclear if federal agents are the ones who intend on showing any particular restraint, given the new guidelines. According to the New York Times, ICE agents have already been targeting church shelters, airports and other areas where immigrants are known to convene.

Two officials in Washington said that the shift [in policy]— and the new enthusiasm that has come with it — seems to have encouraged pro-Trump political comments and banter that struck the officials as brazen or gung-ho, like remarks about their jobs becoming “fun.” Those who take less of a hard line on unauthorized immigrants feel silenced, the officials said.

Brazen behavior by those tasked with deportations, Johnson said, “is opening the door to the kinds of excesses that happened ... across the nation during the Depression—when state and local law enforcement made mistakes and rounded up brown people as their way of general relief reduction. I understand why immigrant communities are very frightened about what could happen.”

In the meantime, only a limited number of Americans seem to even be aware of the gross mistakes their country made in the name of security. While still a state senator, Dunn successfully sponsored the Apology Act, an official mea culpa from the state of California to its Mexican residents—it passed in 2006. He also led efforts to have a memorial erected in La Placita park, the site of the first raids on L.A.’s Mexican community, where it now stands in memoriam.

And yet, when Dunn took his apology proposal to members of the U.S. Congress, no one was interested. “They would say, ‘Immigration is really volatile right now. We’re gonna look like we’re only fighting for Latinos.’ We couldn’t convince anyone to pick it up.”

As for all the records and material unearthed during his research? Dunn said, “Those documents are still sitting in my garage. Nobody really wanted them.”

Those whose families were affected by the deportations—in some cases forever changed—appear no more eager to delve into the sins of the past. “They never talked about it,” said Herrada, “there was a lot of shame associated with it … They didn’t know why they got deported. They didn’t know what they did to bring that on. The only thing they knew was that they were Mexicans—and this only happened to Mexicans.”

She added, “My grandfather still didn’t want to say he was deported. And my father, on his deathbed, said to me, You know, I never liked that word. He was really angry that I had used it.”

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.